Modeling and Experimental Validation of Space Structures with Wiring Harnesses

Power- and data-handling cables, which can account for up to 30% of a satellite's dry mass, couple with the spacecraft structure and impact dynamic response. Structural dynamic measurements suggest that a more complete representation of cable effects is needed to improve model predictive accuracy. To that end, a study was performed to characterize cable harness impacts on dynamic response. From this study, a finite element modeling method supported by empirically determined cable properties and structural behavior was developed. The modeling method was validated with a considerable amount of model simulation and experimental data for a variety of cables attached to a free free beam. At low frequencies, the cable effect was dominated by mass and stiffness, changing the apparent stiffness; damping was a secondary effect. At higher frequencies, where the cables themselves were resonant, the cable effect was dissipative, increasing the apparent damping in addition to affecting the overall frequency response. Tiedown stiffness was found to be an important, but difficult to measure, parameter. Finite element models of a cabled beam were shown to be valid for all cable families studied. As a result, the finite element modeling method itself was validated.